The present invention relates to exercise devices, and methods of exercising, and particularly to isometric exercise methods and devices.
Exercise devices and programs in use today may be classified into two types: isotonic, and isometric.
When performing isotonic exercises, the exerciser's movements are opposed by the force of gravity, or by a spring. All weight-lifting exercises are isotonic exercises. Such exercises are commonly performed using barbells or exercise machines, which utilize either springs or weights to oppose the users's movements.
Isotonic exercise machines typically exercise only a specified muscle or group of muscles, and thus, a variety of different exercise devices may be needed to exercise the various muscle groups throughout the body. Purchasing such a variety of equipment can involve a sizable monetary investment. In addition, a substantial amount of floor space may be required to set up the various exercise machines desired.
Moreover, in isotonic type exercises, the use of fixed weights does not permit compensating for individual variations in energy output from day to day. On one day the exerciser may be at a physical peak and have no difficulty in performing the desired number of repetitions of a particular exercise with a fixed weight comfortably. However, a day or two later the exerciser may not be at that physical peak and may have to struggle to perform the same exercise.
Isometric exercises alleviate many of the problems associated with isotonic exercise, since, in this type of exercise the exerciser pushes or pulls against an immovable object, thereby permitting him to automatically adjust the load on his muscles to match his physical condition.
When performing an isometric exercise, the exerciser typically pushes or pulls against a wall, or a piece of furniture. Alternatively, he may push or pull against himself--e.g. by grasping a portion of his body with a hand. The exerciser tenses a muscle or small group of muscles, then locks it into a fixed position and maintains such tension for an extended period of time. Inherently, this is a static form of exercise, and the exerciser must assume a different position each time he wants to exercise a different muscle or part thereof. Thus, it is extremely difficult, if not impossible, to build strength evenly along the muscle being exercised. Since it is desirable to tone the entire muscle rather than only one part of it, most people prefer to use isotonic exercises, despite their disadvantages.
A problem common to both isometric and isotonic exercises is that neither emphasizes overall cardiovascular fitness. Since these exercises generally utilize only a single muscle or small group of muscles at a time, the entire body is not involved in performing an exercise. While the heart rate of the exerciser may increase during performance of isotonic or isometric exercises, the increased blood flow is required only by the muscles being exercised, therefore resulting in a less than complete exercise of the cardiovascular system.